The present disclosure relates to an interface device, and more particularly relates to a technique for transmitting data from the frontend to backend of a receiver for use in TV sets and other appliances.
A technique for transmitting a variable-length packet for use in communications and other purposes along with a transport stream (TS) used in broadcasting and other fields has been known in the art. In the field of advanced BS digital broadcasting, for example, a TS packet and a type length value (TLV) packet may be transmitted simultaneously (see, for example, ARIB STD-B44 Version 1.0, “Transmission System for Advanced Wide Band Digital Satellite Broadcasting,” Association of Radio Industries and Businesses (ARIB), Jul. 29, 2009). According to this technique, an Internet protocol (IP) packet is transmitted in a TLV format. As devices for transmitting a TS packet and a variable-length packet such as a TLV packet simultaneously, disclosed are a transmitter for sending out a TS packet and a variable-length packet after having multiplexed them together and a receiver for de-multiplexing a multiplexed signal received into a TS packet and a variable-length packet (see, for example, Japanese Unexamined Patent Publication No. 2013-175949).
In such a receiver, after the received signal has been de-multiplexed by a frontend processor into a TS packet and a variable-length packet, these packets are generally subjected to decoding and other types of processing by a backend processor.
The TS packet serving as a data signal as shown in FIG. 7 of Japanese Unexamined Patent Publication No. 2013-175949 may be transmitted in response to not only a clock signal but also two other types of signals as indicated, in particular, by P12 and P13 in EUROPEAN STANDARD, EN 50083-9, “Cable Networks for Television Signals, Sound Signals and Interactive Services Part 9: Interfaces for CATV/SMATV Headends and Similar Professional Equipment for DVB/MPEG-2 Transport Streams,” December 2002.
The receiver disclosed in FIG. 7 of Japanese Unexamined Patent Publication No. 2013-175949 needs to transmit not only a TS packet but also a TLV packet as well. However, neither Japanese Unexamined Patent Publication No. 2013-175949 nor any other document teaches exactly how to transmit the TLV packet.
Thus, to transmit a variable-length packet from the frontend processor to the backend processor, the receiver disclosed in FIG. 7 of Japanese Unexamined Patent Publication No. 2013-175949 may be provided with a terminal or line dedicated to transmitting the variable-length packet.
Providing such a dedicated terminal or line to transmit a variable-length packet, however, increases the overall number of terminals or lines to provide, which could possibly lead to an unwanted increase in the cost and/or circuit size of the receiver. Additionally, the increased number of lines provided may require changing the number of terminals to provide for the backend processor as well.
In view of the foregoing background, it is therefore an object of the present disclosure to provide an interface device having the ability to transmit a TS packet and a variable-length packet without causing an increase in the number of terminals or lines to provide.